Which additional voice feature is commonly seen in hypokinetic dysarthria?

In hypokinetic dysarthria, which is often associated with conditions like Parkinson's disease, one of the hallmark features is reduced variability in voice characteristics. This reduction manifests as a limited range of pitch and loudness fluctuations, leading to a monotone quality in speech. Patients may display a uniform speech pattern, lacking the normal prosodic variations that contribute to expressive communication. Therefore, reduced variability is a defining characteristic of the voice in hypokinetic dysarthria and is important in distinguishing it from other types of dysarthria.

The other features listed do not align with the typical presentation of hypokinetic dysarthria. For instance, hypernasality is more associated with flaccid dysarthria due to a loss of muscle tone affecting the soft palate. Vocal tremor is generally seen in other types such as essential tremor or spastic dysarthria. Excessive breath support is not characteristic of hypokinetic dysarthria as there is typically a restriction in the overall vocal output. Thus, in the context of hypokinetic dysarthria, reduced variability is the feature that stands out.